Coding Obesity in Pregnancy - Updated
If a patient has a diagnosis of obesity (BMI ≥ 30) O99.21__ (obesity complicating pregnancy, childbirth and the puerperium) is an accepted indication for a detailed fetal anatomy survey (CPT 76811) according to published guidelines. To determine BMI in a pregnancy affected by obesity, we recommend utilizing the pre-gravid height/weight to calculate this value. If pre-gravid BMI is not available, it is advised that the physician calculate the BMI at the first pregnancy encounter in their office. Obesity diagnosis codes should be accompanied by endocrine “E-codes” that categorize the class of obesity.
Example #1: A 29-year-old G2P1 presents at 8-week ob visit, and her height/weight obtained calculates a BMI of 29 kg/m2. When the patient returns for ob visit in the 2nd trimester, it is noted she has gained 40 pounds. Her height/weight now calculates a BMI of 35 kg/m2. How would you code the 2nd visit? In this case, the code for excessive weight gain in pregnancy (O26.0__) would be used. ICD-10 code O99.21__ for obesity complicating pregnancy would not be assigned, because the diagnosis of obesity was not present until the subsequent visit. If a fetal anatomy ultrasound was performed in the 2nd trimester, 76805 would be billed, rather than 76811, since O26.0__ is not an indication for 76811.
Example #2: Prenatal records are unavailable for the patient, who presents at 18 weeks to your office for fetal anatomy ultrasound. As no records are available, you obtain a height & weight to calculate her BMI in your office. The BMI is calculated to be 44kg/m2. ICD-10 code O99.212 (obesity complicating pregnancy, second trimester) should be used along with (E66.01) BMI over 40. For BMI’s of (30-39.9) please use (E66.09). The E66.xx series is used to identify the type of obesity. Given BMI > 30, performance of a detailed anatomy ultrasound (76811) would be appropriate. The ICD-10 code for BMI (Z68.1-Z68.45) should NOT be assigned in pregnancy. Chapter 21 of the ICD-10 Official Guidelines for Coding and Reporting states: Do not assign BMI codes during pregnancy.
Examples:
(1) 2nd tri F/U visit & anatomy scan with BMI 35 (BMI 29 at 8w visit)
CPT: 76805 Complete OB Ultrasound
Diagnosis Code(s): O26.0__ Excessive weight gain in pregnancy
(2) 2nd tri visit & anatomy scan; BMI 44, no prior prenatal records
CPT: 76811 Detailed anatomy ultrasound
Diagnosis Code(s): O99.212 Obesity complicating pregnancy, 2nd trimester; E66.01 BMI >40
Summary
- BMI ≥ 30 is a diagnosis of obesity
- Obesity complicating pregnancy is based on pre-gravid BMI or BMI at first obstetric visit
- Obesity complicating pregnancy is an accepted indication for detailed fetal anatomic survey
- Perinatal obesity diagnosis codes should be accompanied by E-codes to describe the class of obesity
- Do not assign BMI Z-codes during pregnancy